Genes were taken from two acorn worms –namely Ptychodera flava from Hawaii, and Saccoglossus kowalevskii from the Atlantic Ocean –for analysis. The worms are characterised by slits embedded in their guts for breathing, and the absence of limbs. Though they do not look like humans in any way whatsoever, the researchers believe they might be our “distant cousins” – a conclusion that might possibly boost research in the field of evolutionary biology.

The team, led by Oleg Simakov from the Okinawa Institute of Science and Technology Graduate University in Okinawa, Japan, found around 14,000 genes shared by both humans and the worms – this is equivalent to 70 % of the human genome.

The shared genes are found in existing deuterostomes, namely humans, and all vertebrates as well as sea stars, octopus, squids, and their kin. The acorn worms, allegedly dating back to the time when the first deuterostomes appeared (570 million years ago), are said to be “our most ancient deuterostome relatives”. The genes can themselves be traced back to a creature living during the Cambrian explosion, over 500 million years ago, which is thought to be the common ancestor of humans and the worms.

Given the history of acorn worms, scientists believe studying them can refine our understanding of how such ancient genes can code for both simple features in ancient animals and more evolved characteristics in later species that have otherwise equivalent functions; for instance, genes controlling acorn worms’ slits (through which they feed) that are situated between their mouth and oesophagus might be associated with the development of gills in other deuterostomes, and even with the human pharynx (the cavity connecting the mouth to the oesophagus).

“The genomic data fills in the gaps in our understanding of their evolution,” comments Simakov.

Simakov now wishes to delve deeper into genomic analysis with the aim to finding the common genes between humans and other life forms on Earth.